Generation of carbon tripods on copper by chemical vapor deposition

We report the first observation of large graphitic capped clusters with thr eefold symmetry (tripods), They were generated under the diamond growth con ditions by the chemical vapor deposition process activated by hot filaments on a Cu(lll) surface while conditions of very poor diamond nucleation (10( 4)-10(5) cm(-2)) are fullfilled. They were characterized by direct high res olution imaging and selected area diffraction. Furthermore, a lot of them a re connected. The behavior of hydrogen radicals to curl and to close limite d-size graphitic planes is emphasized to explain their formation. These tri pods appear to be readily stable carbon as they form only after other limit ed-size graphitic clusters such as graphite lumps or bucky onions. It is th us expected that the chemical vapor deposition process is a quite relevant preparation method to grow in a controlled way new forms of carbon with a n arrow size distribution.